Class File

tables/file.py:604–3032

The in-memory representation of a PyTables file. An instance of this class is returned when a PyTables file is opened with the :func:`tables.open_file` function. It offers methods to manipulate (create, rename, delete...) nodes and handle their attributes, as well as methods to trav

class File(hdf5extension.File):
    """The in-memory representation of a PyTables file.

    An instance of this class is returned when a PyTables file is
    opened with the :func:`tables.open_file` function. It offers methods
    to manipulate (create, rename, delete...) nodes and handle their
    attributes, as well as methods to traverse the object tree.
    The *user entry point* to the object tree attached to the HDF5 file
    is represented in the root_uep attribute.
    Other attributes are available.

    File objects support an *Undo/Redo mechanism* which can be enabled
    with the :meth:`File.enable_undo` method. Once the Undo/Redo
    mechanism is enabled, explicit *marks* (with an optional unique
    name) can be set on the state of the database using the
    :meth:`File.mark`
    method. There are two implicit marks which are always available:
    the initial mark (0) and the final mark (-1).  Both the identifier
    of a mark and its name can be used in *undo* and *redo* operations.

    Hierarchy manipulation operations (node creation, movement and
    removal) and attribute handling operations (setting and deleting)
    made after a mark can be undone by using the :meth:`File.undo`
    method, which returns the database to the state of a past mark.
    If undo() is not followed by operations that modify the hierarchy
    or attributes, the :meth:`File.redo` method can be used to return
    the database to the state of a future mark. Else, future states of
    the database are forgotten.

    Note that data handling operations can not be undone nor redone by
    now. Also, hierarchy manipulation operations on nodes that do not
    support the Undo/Redo mechanism issue an UndoRedoWarning *before*
    changing the database.

    The Undo/Redo mechanism is persistent between sessions and can
    only be disabled by calling the :meth:`File.disable_undo` method.

    File objects can also act as context managers when using the with
    statement introduced in Python 2.5.  When exiting a context, the
    file is automatically closed.

    Parameters
    ----------
    filename : str
        The name of the file (supports environment variable expansion).
        It is suggested that file names have any of the .h5, .hdf or
        .hdf5 extensions, although this is not mandatory.

    mode : str
        The mode to open the file. It can be one of the
        following:

            * *'r'*: Read-only; no data can be modified.
            * *'w'*: Write; a new file is created (an existing file
              with the same name would be deleted).
            * *'a'*: Append; an existing file is opened for reading
              and writing, and if the file does not exist it is created.
            * *'r+'*: It is similar to 'a', but the file must already